(AP) GUATEMALA CITY - A team of 200 U.S. Marines began patrolling Guatemala's western coast this week in an unprecedented operation to beat drug traffickers in the Central America region, a U.S. military spokesman said Wednesday.

The Marines are deployed as part of Operation Martillo, a broader effort started last Jan. 15 to stop drug trafficking along the Central American coast. Focused exclusively on drug dealers in airplanes or boats, the U.S.-led operation involves troops or law enforcement agents from Belize, Britain, Canada, Colombia, Costa Rica, El Salvador, France, Guatemala, Honduras, the Netherlands, Nicaragua, Panama and Spain.

"This is the first Marine deployment that directly supports countering transnational crime in this area, and it's certainly the largest footprint we've had in that area in quite some time," said Marine Staff Sgt. Earnest Barnes at the U.S. Southern Command in Miami.

It was 50 years ago when the U.S. military last sent any significant aid and equipment into Guatemala, establishing a base to support counter-insurgency efforts during a guerrilla uprising. That movement led to 36 years of war that left 200,000 dead, mostly indigent Maya farmers. The U.S. pulled out in 1978.

Guatemalan authorities say they signed a treaty allowing the U.S. military to conduct the operations on July 16. Less than a month later an Air Force C-5 transport plane flew into Guatemala City from North Carolina loaded with the Marines and four UH-1 "Huey" helicopters.

After two weeks of setting up camp, establishing computer connections and training at the Guatemalan air base at Retalhuleu, the Marines ran through rehearsal exercises, Barnes said. Last week, their commander "gave us the thumbs up" to begin active operations, he said.

This week the Marines have been patrolling waterways and the coastline, looking for fast power boats and self-propelled "narco-submarines" used to smuggle drugs along Central America's Pacific Coast. U.S. officials say the "drug subs" can carry up to 11 tons of illegal cargo up to 5,000 miles.

Col. Erick Escobedo, spokesman for Guatemalan Military Forces and Defense Ministry, said that so far the Marines have brought about the seizure of one small-engine aircraft and a car, but made no arrests. He said he expected the Marines to be in Guatemala for about two months.

If the Marines find suspected boats, Barnes said, they will contact their Guatemalan counterparts in a special operations unit from the Guatemalan navy that will move in for the bust. Barnes said the Marines will not go along on arrest missions, but they do have the right to defend themselves if fired on.

Eighty percent of cocaine smoked, snorted and swallowed in the U.S. passes through Central America, according to the Drug Enforcement Administration. Eight out of every 10 tons of that cocaine are loaded on vessels known as "go fasts," which are open hulled boats 20 to 50 feet long with as many as four engines, according to the Defense Department.

In a recent congressional briefing in Washington, Rear Adm. Charles Michel said the boats, carrying anywhere from 660 pounds to almost four tons of cocaine, typically leave Colombia and follow the western Caribbean coastline of Central America to make landfall, principally in Honduras. In the Pacific, the same type of vessels will leave Colombia or Ecuador and travel to Guatemala, Panama, Costa Rica or Mexico, Michel said.

"We fight a highly mobile, disciplined and well-funded adversary that threatens democratic governments, terrorizes populations, impedes economic development and creates regional instability," he said, noting that authorities are able to stop only one out of every four suspected traffickers they spot.